Furnace door and conveyer control



' Dec. 27, 1932.

H. G. M ILVRIED ET Al. ,643

FURNACE DOOR AND CONVEYER CONTROL Filed Sept. 9, 1931 2 Sheets-Sheet l jyzvenfars 6. M L V1? IED K. 5. WEST mam @MM/ FURNACE DOOR AND CONVEYER TONTROL Filed Sept. 9, 1931 2 Sheets-Sheet 2 H. 6. M 1 12/50 K. 5.14 53?" Patented Dec. 27, 1932 UNITED STATES ra'rsnr 5'1 HOWARD G..MCILVRIED AND KLINE ,3. WEST, OF GARY, INDIANA, ASSIG-NORS TO AMERICAN SHEET AND TIN PLATE COMPANY, .51 CUREORATION OF NEW JERSEY FURNACE DOOR AND GONVEYEE CQNTROL Application filed September 9, 1931.

This invention relates to a door and conveyer control for a continuous heating furnace, one of the objects of the invention being to provide a means whereby, when the operator of the rolling mill opens the door of the the parts shown in Figure 1.

Having reference to thesedrawings, there is shown a continuous heating furnace 2 having an interior Work conveyor 3 and an exterior work conveyor f1, these two conveyors being interconnected by a drive 5 to be synchronously driven by an electric motor 6. A vertically slidable door 7 is positioned be tween these conveyers to close the discharge opening in the furnace.

In this instance the work carried through the furnace consists of packs of metal plates 8, it being necessary to withdraw these units from the furnace through the door 7 for working by the rolls 9. To stop the work units 8 proximate the door 7 so that they will be ready for withdrawal from the furnace Without the necessity of moving the conveyer 3 .to any great extent, a finger member 10 fixed to a shaft 12 which carries a cam 13 is positioned in the furnace 2 at this door. This cam trips a limit switch 14 which is connected in circuit with the motor 6 for stopping the same. When the conveyer 8 is operated to carry the work units 8 through the furnace these units engage the finger member 10 so that the switch 14 is operated and the motor 6 stopped, the units 8 thereby being each successively stopped in position for immediate delivery through the door when the motor 6 is restarted.

A foot switch 15 is located near the rolls 9 and is connected to start a motor 16 geared to a shaft 17. This shaft 17 carries a lever member 18 which is connected to the sliding $eria1 No. 561,976.

door 7 so as to raise the same. This shaft also carries a pair of cams 19 and 20, cam 19 being arranged to simultaneously operate a pair of limit switches 21 and 22. Limit switch 21 is connected with the motor 16 so as to stop it when the door is completely opened, and the switch 22 is connected so as to start the motor 6.

In order to move the finger member 10 out of tl e path of the Work units 8 a solenoic 23 is levered to the shaft 12 and connected to the switch 22 for energiZation. When the motor 6 is started a work unit 8 is delivered through the door 7 and onto the exterior work con- Veyer 4, a bar 25 being arranged in path to be depressed thereby. This bar simultaneously operates limit switches 26 and 27, the limit switch 26 being connected to deenergize the solenoid 23 so that the finger memberlO returns to its original position and the motor 6 is stopped. The limit switch 26 is also connected so as to operate the motor 16 in the reverse direction to close the door 7, the limit switch 16 being then operated by the cam 20 to stop this motor. 7

The limit switch 27 is connected to the motor 6 to prevent its momentary stoppage during the time it takes the finger member 10 to return to its original position.

Qne method of interconnecting the parts so as to accomplish the described functions is as follows:

Direct current lines 28 and 29 are connected by a switch 30 to the motor 6. The line 28 is connected through a relay 81 to the field 82 of the motor 6, a shunt field 33 being arranged between it and the line 29, the motor 6 being dynamically braked by a resistance 84 shunted across its armature through a relay 85. The furnace is started by closing a switch 86 which is connected by means of a line 87 to the line 29 and through the operating coil of a relay 38 to a line 39 leading to the line 28. The relay 88, being thus energized, closes the 95 circuit from the line 29 through the finger operated switch 14 and the operating coils of the relays 81 and 35 to the line 28. The relay 31 closes the circuit to the motor 6 and the relay 85opens the dynamic braking circuit so that the motor 6 starts and drives the furnace conveyors.

It is to be understood that the work units are to be placed on the interior conveyor of the furnace at its rear end and advance through the furnace towards the door 7. During this advance they each strike the finger member 10 so as to open the switch 1% and thus deenergize relays 31 and 35, so that the driving current to the motor 6 is cut oil and the dynamic circuit is again closed. The interior conveyor is thus stopped with a work unit proximate the door 7 and ready for immediate delivery. When the operator of the rolls 9 desires a work unit for wm'king he uses the foot operated switch 15 to close the circuit to the coil of the double contact relay to the line 23. It also energizes the relay ll which by-passes the current thereabout so that when the operator releases his foot this circuit will. be maintained.

he door lifting motor 16 is energized, through alternaing current lines 42, through a pair of relays l3 and it which are arranged in circuit therewith for reversing the direction of the current through the motor 16 by operation of relay 40. In this present instance, the right-hand contact of relay 40 is clos d so that this motor is operated to raise the door '7. When the door '7 is completely raised the cam 19, carried by the operating shaft 1'7, ope ates the limit switches 21 and 22. The switch 21 is thus opened so as to open the circuit to the relay 43 so that the circuit to the motor 16 is broken and it stops.

The limit switch 22 is closed by the door in its present position and energizes the relay d so that its loft-hand contact closes the circuit from the line 29 through the solenoid 23 to line 28, thus moving the finger out of the path of work units carried by the conveyer 3. Its right-hand contact simultaneously closes the circuit to the relays 31 and 35 so that the motor 6 is again operated to drive the conveyor in the manner first mentioned. is the conveyor was stopped with a work unit proximate the door 7 it follows that this unit is immediately deposited on the exterior conveyer where it depresses the bar 25 so as to operate the limit switches 26 and 2'? togethor.

The switch 26 is connected so as to be opened at this moment, thus deonergizing rolays and ii, the right-hand contact of the relay at) being broken thereby and the left contact closing the circuit to the relay 4% which, in turn, closes the reversing circuit to the motor 16 so that this motor closes the door 7. Vhen the relay a1 is doenergized it breaks the circuit to the relay which deenergizes the solenoid 23 and allows the finger member 10 to swing back into the path of the work units carried by the conveyor 3. The cam operated switch 46 is opened by the closing of the door 7 and deenergizes switch 44:, stopping the motor 16.

During the time it takes the finger member 10 to swing back into a position where the contact l i will complete the circuit to the relays 31 and 35 there will be an open circuit, the latter two relays being deenergized during this interval so that the motor 6 is stopped and dynan'iically braked. The switch 27 operated by the bar 25 avoids this momentary stopping by completing the circuit during this interval,

By the use of this invention it is possible for the operator of the rolls 9 to withdraw a unit of work from the furnace 2 very quickly, there being no danger of the door 7 remaining open and allowing loss of heat from this furnace as is now quite customary.

These operations are all automatic and the parts needed may be made of a simplified construction and sutficiontly large to withstand the intense heat to which they are exposed. The circuit illustrated may, of course, be varied at will and it is to be understood that a specific form of the invention has been shown in accordance with the patent statutes and not with the intention of limiting the scope of the invention exactly thereto, except as will be defined by the appended claims.

We claim:

1. In combination with a continuous heating furnace having a discharge opening closed by a door, means for moving work through said furnace, means arranged in the path of work moved by said first named means and adjacent said opening for stopping the movement of work through said furnace, means for moving said door and means for moving said second named means out of the path of work units upon movement of said door.

In combination with a continuous heating furnace having a discharge opening closed by a door and with one or more conveyors for moving work therethrough and out through this opening, a movable member arranged in. said furnace adjacent said opening and in the path of work moved by said conveyors, means operable by movement of said member for stopping said conveyors, means for opening said door and means operable by the movement of said door for starting said conveyors and moving said member out of the path of work moved by said conveyor.

3. In combination with a continuous heating furnace having a discharge opening closed by a door and with one or more conveyors for moving work therethrough and out through this opening, a movable member arranged in said furnace adjacent said opening and in the path of work moved by said conveyors, means operable by movement of said member for stopping said conveyers, means for opening said door, means operable by the movement of said door for starting said conveyors and for moving said member out of the path of work moved by said eonveyers, and means operable by the discharge of Work through said opening for closing said door and returning said member to its original position.

4. In combination with a continuous heating furnace having a discharge opening closed 

